Drawbench



W. RODDER June 7, 1949.

DRAWBENCH 9 Sheets-Sheet 1 Filed June 16, 1944 INVEN TOR W/L 1. IAN RODDEE ATTO/P/VEYS W. RODDER June 7, 1949.

DRAWBENCH 9 Sheets-Sheet 2 Filed June 16, 1944 INVENTOR. W/LL/AM )E'ODDEE BY I June 7, 1949.

w. RODDER DRAWBENCH 9 Sheets-Sheet 3 Filed June 16, 1944 INVENTOR. -vV/L L /AM 2202351? 6 A TTOENEYS June 7, 1 949, w, R DDER 2,472,231

DRAWBENGH Filed June 16. 1944 9 Sheets-Sheet 4 INVENTOR. w/u IAM EOPDEIE A 7'TOENEY5 W. RODDER June 7, 1949.

DRAWBENCH Filed June 16, 1944 9 Sheets-Sheet 6 m3 %N g w. RODDER 7 31 DRAWBENCH 9 Sheets-Sheet 7 IN V EN TOR W/L L IAM EODDEE June 7, 1949.

Filed June 16, 1944 H v\\ W 65 3 u June 7, 1949. w RODDER 2,472,231

DRAWBENCH Filed June 16, 1944 9 Sheets-Sheet 8 INVENTOR. W/LL/AM EQDDEIE A fiMM A 7 ram/[X5 Patented June 7, 1949 DRAWBENCH William Rudder, Youngstown, Ohio, assignor to The Aetna-Standard Engineering Company, Youngstown, Ohio, a corporation of Ohio Application'June 16, 1944, Serial No. 540,630

8 Claims. 1

This invention relates to drawbenches and more particularly to improvements in apparatus for loading tubes on to the mandrel rods of drawbenches.

A general object of the invention is the provision of an apparatus wherein a plurality of mandrel rods 'may be positioned adjacent a loading rack and loaded with tubes while at the same time a plurality of tubes are being drawn through the dies of the drawbench. Another object of the invention is to provide an apparatus which is particularly adapted for such multiple drawing operations, and which is also capable of utilization in operations where only one tube is drawn at a time. A further object is the provision of such an apparatus which can be operated rapidly with little effort on the part of the machine operator and which will have a high productive capacity in service. Another object of the invention is the provision of a mandrel loading mechanism adapted for single or multiple drawing operations wherein simple and eflicient means are provided for advancing the mandrels into drawing position adjacent the dies and retracting them therefrom. Another object is the provision of a mandrel loading apparatus wherein the mandrel or mandrels in loading position are in substantial alignment with a substantially horizontal loading rack, whereby the tubes may be fed over the mandrels easily and rapidly. Another object is to provide such an apparatus wherein the mandrel or mandrels in loading position are substantially horizontal and parallel with the mandrel or mandrels in drawing position. Other objects and advantages of the invention will become apparent from the following description of a preferred form thereof, reference being made to the accompanying drawings.

According to a preferred form of my inventionI accomplish the above objects by providing a mechanism in which the mandrel bars and associated guides for supporting the tube and mandrel bars are mounted in rotatable carriers, the arrangement being such that one mandrelbar or group of mandrel bars is positioned adjacent the die or dies for the drawing operation, while another mandrel bar orgroup of mandrel bars is positioned diametrically opposite the first bar or bars adjacent a loading rack so that the tubes may be readily loaded onto them, while the tubes positioned on the first mandrel .bars

.are being drawn through the dies. After the drawing operation is completed, the carriers are simultaneously rotated to position the loaded mandrel bars adjacent the loading rack. Means such as an air or hydraulic cylinder are provided for advancing the mandrel bars toward the die into drawing position and for retracting them therefrom. Preferably the loading rack is positioned over the drawbench in accordance with conventional practice, and the tubes are fed over the empty mandrel bars by a pusher or a set ofpinch rolls. Suitable controls are provided so that the various operations can be controlled by an operator stationed adjacent the die stand.

In the drawings Figures 1 and 2 together co stitute an elevation of a bench embodying one form of my invention; Figure 3 is a fragmentary plan view of the drawbench shown in Figures 1 and 2, the figure illustrating a portion of the bench adjacent the die stand, as indicated by the line 3'3 of Figure 2; Figure 4 is a transverse section on an enlarged scale as indicated by the line 4-4 of Figure 1 and illustrating one of the supporting cages or carries for the mandrel rods; Figure 5 is a sectional view as indicated by line 5-5 of Figure 4; Figure 6 is an end elevational view of the bench shown in Figure 1 as indicated by the line 6-6 of Figure 1, the view being on an enlarged scale and illustrating the mechanism for holding the ends of the mandrels and advancing and retracting them; Figure 'l is a sectional detail of this same mechanism indicated by the line |--'I of Figure 6; Figure 8 is a transverse sectional view of the loading rack and associated mechanism asindicated by the line 8-8 of Figure 2; Figure 9 is a detail, on an enlarged scale, of the elevating mechanism for the loading rack, the view being taken along line 9-9 of Figure 8; Figures 10 and 11 are elev'a-- tional views of a modified, and in some respects preferred, embodiment of the invention; Figure 12 is a fragmentary plan view of the portion of the bench adjacent the die stand, as indicated by line 12-42 of Figure 11; Figure 13 is an enlarged elevation partly in section, illustrating the portion of the mechanism adjacent the die stand. including the pinch rolls for feeding the tubes over the mandrel rods; Figure 14 is a transverse view taken along the lines l4l4 of Figure 13; Figure 15 is a longitudinal sectional detail showing the construction of the rotary mandrel rod carrier; Figure 16 is an enlarged sectional detail showing the mechanism for holding, advancing and retracting the mandrel rods; Figures 17, 18 and 19 are transverse sectional views as indicated by the lines ll-l'l, l8--|8 and iQ-II respectively, of Figure 16, showing the mandrel holding the advancing and retracting mechanism; Figures 20 and 21 are transverse sectional details illustrating the mechanism for rotating the mandrel rod carrier, Figure 20 being taken along line 2023 of Figure 11, and Figure 21 along line 2|2| of Figure 22; Figure 22 is an elevational detail of this mechanism as indicated by the line 22-22 of Figure 20; Figure 23 is a transverse view taken along the line 2323 of Figure 13;- Figure 24 is a side view of the pinch rolls and associated mechanism as indicated by the line 24-24 of Figure 23; and Fi ure 25 is a fragmentary view of the loading rack for the tubes.

As shown in Figures 1 and 2, my invention may be applied to a drawbench of any ordinary construction, for example, embodying a die stand III, a bed or track I I on which the carriage l2, which is provided with suitable gripping jaws, operates. The carriage is driven in the conventional manner by a chain l3 which is engaged by the hook l4 and is returned to the die-stand by a conventional return mechanism. The details of the carriage and the drive mechanism form no part of the present invention and will 'not be described or illustrated further herein. The drawbench may be provided with a loadin rack indicated generally at l5, disposed at one side of and extending over the bed, and the,

drawbench may include suitable mechanism for discharging the drawn tubes such as the discharge arms l6, preferably constructed and ope erated in accordance with the disclosure of the.

Rodder and Strock Patent No. 2,262,432.

1 The mandrel bar operating mechanism is indicated in general in Figures 1, 2 and 3 and is shown in greater detail in Figures 4 to 7 inclusive. In the present embodiment of my invention the apparatus is shown as adapted for simultaneous drawing of two tubes. To accomplish this I have provided two sets of mandrels and mandrel rods, the mandrel rods 25 and 2| provided with mandrels 22 and 23 constituting one set, while the mandrel rods 24 and 25 and associated mandrels constitute the other set. Mandrel 25, mounted on rod 24 is shown in Figure 2. The mandrel carried by rod 25 does not appear in the drawings but is of the same construction as all of the other mandrels. The mandrel rods are anchored at their ends away from the die stand in the rotary mandrel rod holder 28 (see Figures and 6) and extend toward the die stand within pairs of supporting or guiding tubes 25, 30 and 3|, 32 for the upper and lower sets of mandrel rods, re-

spectively. These tubes are supported by a plurality oi rotatable cages indicated in general at 33 in Figures 1 and 2 and illustrated in detail in Figures 4 and 5.

' In order to interchange the positions of the mandrel rods 20 and 2| and 24 and 25, the mandrel rod holder 28 and the several rotor cages or supports may be rotated through an arc of 180. This is accomplished by supporting each of the rotatable cages by means of rollers 34 mounted in'an annular housing member 35 suitably supported by the base members 35 of the apparatus. The cage members 33 are provided with external gear teeth as at 31, the rollers 34 being recessed as at 38 to clear the gear teeth, while the flanges 39 of the rollers engage the annular surfaces of the members 33 to support and center them accurately. The rotational movement of each of the members 33 may be obtained through a pinion 40 associated with each member and driven bythe electric motor 4| (see Fig. 1) through a 4 suitable speed reducer 42 which drives the line shaft 43.

As shown particularly in Figures 6 and 7, the mandrel rod holder 28 is mounted for rotation on suitable bearings carried by the supporting member 45 and is provided with teeth 46 for engagement with the elongated pinion." also mounted on the shaft 43. Thus by operation of the motor the mandrel rod holder and the several supporting cages may be rotated simultaneously to carry the mandrel rods from drawing position adjacent the die into loading position and from loading position into drawing position.

.In order to advance and retract the mandrel bars toward and away from the die, the supporting member is slidably mounted in the support 48 as shown and is provided at its outer end with a bracket 43 which engages the piston rod 50 of the fluid pressure cylinder apparatus 5|. By admission of fluid under pressure to one end or the other of the cylinder, the mandrel rods can be moved back and forth as required, this motion being permitted without disengaging the mandrel rod holder from the pinion 41 because of the length of the teeth of the pinion. It will be noted that when the mandrel rod holder is in its forward 32 all remaining stationary. The flow of fluid under pressure to and from cylinder 5| may be controlled by conventional valve and piping arrangements, which are not illustrated herein.

In order to insure accurate positioning of the mandrels with respect to the dies, stop means are provided for the rotary members 33, the stops being indicated at 53, 54 and 55 in Figure 4. The motor 4| is preferably controlled by limit switches so that the rotating mechanism will always be stopped without damage or excessive shock with one or the other sets of mandrel bars correctly in alignment with the dies carried by the die stand.

As noted above, while the tubes on the lower set of mandrel rods are being drawn through the dies, the upper set of mandrel rod is being loaded with other tubes. By this arrangement no time is lost by the loading operation, and high rates of production can be obtained. Preferably this loading operation is carried out by means of the loading rack mechanism indicated generally at l5 in Figures 2 and 3, and as shown in Figures 8 and 9 comprising an elevating platform made up of a plurality of vertical members 6 sloping supporting members 62, and sloping guide members 53. Groups of these members extend along the bench, providing a trough adapted to receive a number of tubes to be drawn, and by means of rangedto leave a space between them for the ver- 'tical member as carrying pairs of guide rollers Ii and I2. I

The line shaft I3 driven by motor M is provided witha plurality of sprockets 15, one' sprocket being positioned adjacent each vertical the bottom end thereof. The motor 64 may be controlled by suitable push button controls adiacent the die stand so that by operation of the motor in the required direction, the operator can raise or lower the platform as he sees fit.

The operator controls the elevating mechanism so that as many tubes as are to be drawn will'roll off the top of the pile over the upper guide member 65 and onto the loading platform 86. In the present instance the mandrels are arranged in pairs so that two tubes will be required for each operation. The operator starts the tubes over the mandrel rods which are in advanced position adjacent the die and then by means of the pusher I9 which is driven by the motor 80 and associated mechanism through the cable 8|, feeds the tubes over the mandrel rods and into the guide tubes 29 and 30, for example. When the tubes have been fed over the mandrels, the pusher I9 may be returned to the position shown in Figure 2 of the drawings whereupon the platform is ready to receive tubes for the next operation. The pusher mechanism is also preferably controlled by push button controls disposed adjacent the die stand and may be of the general type disclosed in greater detail in the Smith Patent No. 2,196,155, issued April 2, 1940.

To summarize the operation of the device, assuming that a new run is being started with no tubes in the drawbench, the first operation is to load a relatively large number of pointed tubes onto the loading rack mechanism I! with the pointed ends of the tubes away from the die stand Ill, i. e., to the right in Figure 2 of the drawing. The operator then operates the elevating mechanism by suitable push button controls for the motor 84 to raise the platform members 82 until a number of tubes corresponding to the number to be drawn simultaneously have rolled over the member 65 onto the loading platform 66. In the present instance as there are two mandrel rods in each set, two tubes T as indicated in Figure 8 would be positioned on the platform 66. Then with the mandrel rods in advanced position toward the die stand. the operator guides the tubes manually over the mandrels and by operation of the pusher motor 80 causes the pusher I! to feed the tubes onto the mandrel rods. The operator then actuates the cylinder Iii, preferably by means of solenoid valves controlled by push buttons, to retract the mandrel rods away from the die stand. Then the motor ll is energized to rotate the entire mandrel bar supporting mechanism to position the loaded mandrel bars and their guides 3| and 32 adjacent the dies carried by the die stand. The cylinder Si is then oper ated in reverse direction to advance the mandrel bars toward the die stand which will insert the pointed ends of the tubes into the die openings, and the drawing operation is then carried out in the usual manner.

While the carriage I2 is traveling away from the die stand and drawing the first set of tubes through the die, the operator repeats the loading process with respect to the other set of mandrel bars which are now disposed on the level of the loading 8. The-loading operation can easily be carried out in the time required'for the drawing operation, and thus the productive efflciency of the bench is very high, for the mandrel rod supports can be rotated to place the loaded mandrel rods in position and the rods advanced to insert the ends 01' the tube into the die while the carriage is being returned toward the die stand after the drawing operation has been completed. Thus there is practically no lost time and the drawing operation can be carried out as fast as the carriage can be operated back and forth along the bed.

In the modification of the invention shown in Figures 10 to 24, inclusive, the fundamental principles are the same as in the form just described.

but the details of the structure are different. In

this form of my invention, which is shown as adapted to a more or less conventional drawbench having a die stand ill, a bed till, a carriage I02 driven by a chain III, the loading mechanism is carried by a framework indicated generally at I, and consists of a large tubular member indicated generally at I05 within which the several mandrel rods and their supports are mounted.

The tubular member, which may be built up from sections of steel pipe I01, is supported for rotation in bearings I08. The tubular member may be rotated through by the mechanism indicated in general at I" in Figure 2 and shown in detail in Figures 20, 21 and 22. The mandrel rods H0 and Iii are arranged in groups of three in the present embodimentof the invention, the rods ill constituting one group and the rods Ill constituting the other group. As shown in Figures 13 and 14, these rods are provided with plugs or mandrels H2 and ill, respectively, and are disposed within tubes Ill and N5, the tubes in him being supported by a plurality of spaced clamping members secured within the cylindrical member I05.

As shown particularly in Figures 13, 14 and 15, the clamps for supporting the tubes are each made up of a segmental member H6 secured to the tube as by cap screws Ill and havin another clamping member 8 secured thereto as by cap screws 9. Members Iii and III are provided with semi-circular recesses which together form circular openings to receive the mandrel suppdrting tubes. It will be noted that openings as at li'l are provided adjacent the clamp in the tube sections lli'l making up the cylindrical memher "I, thus permitting the easy changing of the clamps to accommodate diiIerent sized mandrel supporting tubes. 7 As shown in Figure 15 the clamps are preferably disposed adjacent the juncu l'i'e of two tube sections Ill! and adjacent a bearin III.

The tubular mandrel supports Ill and iii are also preferably made'in sections, and as shown in Figure 15, the ends of the sections are preferably flared as at Iii. Thus any burr that may be formed in welding the sections together is spaced away from the inner cylindrical surface of the tubes H4 and there is no possibility of damaging a tube which is being drawn or loaded onto a mandrel rod, by reason of any rough surfaces at the joints between the sections of the mandrel supporting tubes.

The mechanism for advancing and retractins the mandrel rods is shown in Figures 16, 17, 18 and 19. As there shown the hollow mandrel rods ill and iii are secured by suitable couplings to enlarged extensions in and ill which in turn guano:

are slideably supported in threaded sleeves I26 and I2 and are limited in their endwise move: ment toward the die stand by nuts I21 and I26. The sleeves I26 and I26 are mounted in the semicircular plates Ill and I32, respectively. By ad.- justing the sleeves in the plates, the effective length of the mandrel rods can be varied and the mandrels properly positioned with respect to the dies. Lock nuts are provided for securing the sleeves I25 and I26 in their adjusted positions. and springs I26 and I3. surround the tubular extensions I23 and I2l and urge the mandrel bars toward the die stand, the amount of movement possible being limited by the nuts in and I26. The springs permit the mandrel rods to move away from the die stand during the drawing operation, if necessary.

In the present modification, the mandrel rods are hollow, lubricant being supplied to the mandlel plugs through the rods. and to this end, lue bricant under pressure may be supplied. through the flexible conduits I33 and Illa to the manifolds Ill and I 35 where the fluid is distributed tlolzhe flexible conduits I36 and I 31, respectively. e conduits I36 each are connected to one of the tubular extensions I25 and the conduits I 31 to extensions I2l through suitable fluid couplings. The flexible conduits permit advancing and retracting of the mandrel rods without disturbing fluid connections to the interior thereof, while the conduits I33 and Illa permit rotation'of the entire assembly, these last conduits. being supported by pins Ill carried by plates I 3| and.l32.

In order to advance and retract the mandrel rods toward and away from the die stand, bydraulic cylinders Ill and I l2 are provided. These cylinders are carried by suitable brackets within the last section III of the tubular member I05, are provided with pistons which actuate piston rods Mia and Il2a connected to plates Ill and I32, respectively. Upon admission of fluid under pressure to the end of cylinder IlI toward the die stand, the piston and piston rod Illa will be moved rearwardly in the cylinder away from the die stand. thus moving the supporting plate Ill, sleeves I25 and mandrel rods III away from the die stand. Cylinder 2 may be operated similarly to move mandrel rods III away. from the die stand. The rods are advanced toward the die by admitting fluid to opposite ends of the cylinders. It will be noted that with this arrangement the mandrel rods of one group may be advanced orretracted independently of the rods in the other group. Actuating fluid may be supplied through conduits I b and lb.

The retracted position of the mechanism is in'-' dicated in dotted lines in Figure 16, the flexible conduit I33 and Illa being of sumcient length to accommodate the travel.

- It will be noted that when the mandrel rods are in their advanced position as shown in the drawings, the supporting plates I3I and I32 ene sage and are supported against movement to. ward the die stand by the end of tube I05 which thus acts not only to support and rotate the mandrel rods, but also to take the strain on the man.- drel rods occasioned by the drawing operation. The plates I3I and I32 are supported in their retracted position by supporting rods Illa and I32a, respectively, which are slideably mounted in guides IlIb and Il2b, supported with the tubularmember I55 4 As shown particularly in Figures 13 and lathe supporting member-I66 which is nearest-the die I01 toward the die stand. Thus this member is composed of a lower portion Ill which is welded to the bed or frame member IM and an upper member Ill securely bolted thereto. The members I43 and Ill retain within them the bearing sleeve Il8 which in turn supports the bushing us which is secured as by welding to the exterior of the tube section I0'I nearest the die stand. At their ends toward the die stand the members 3 and Ill are provided with inwardly extending flanges I which act as thrust members to resist movement of the tube I0'I toward the die stand. At their opposite ends, flange members I5I are secured to the members Ill and Ill to provide inwardly extending thrust flanges which engage the flange I52 of the bearing sleeve to prevent movement of the tube I01 in a direction away from the die stand.

By this means the supporting tube is maintained in accurate predetermined relationship to the die stand so far as longitudinal movement of the tube is concerned. The vertical and horizontal positioning of the tube is effected by the bearings contained within the several members Ill.

As shown in Figure 15, for example. the remaining supporting members I06 are merely provided with hearing sleeves I53 which cooperate with thebearings I 5l secured to the exterior of the tube; no means being provided in these bearings to prevent longitudinal movement of the supporting tube I05.

The tube I05 is rotated throughout 180 to interchange the position of the mandrel rods I I0, III and their associated mandrels and supporting tubes by mechanism illustrated particularly in Figures 20, 21 and 22. As there shown, the tube I05 has secured to it, as by welding, two lugs I55 and I56 to which the ends of chain sections I51 and I58 are secured. The other ends of chains I51 and I58 are secured to lugs I59 and I60, respectively, which aremounted on a drum I6I of the same diamete'i as the tube I05. This drum is carried by a shaft I62 supported from the frame I0l as by bracket members I63, and it will be evident that rotation of the drum in either direction will result in corresponding rotation of the tube I05.

Preferably the drum I6I is rotated by means of an air cylinder I6l containing a suitable piston, not shown, to which the piston rod I65 is connected. The piston rod is pivoted as at I66 to an arm I61 which in turn is secured to the segmental gear I68 meshing with the pinion I69 which is keyed to the shaft I62 so that rotation of the pinion will result in rotation of the drum iii. The cylinder I is carried by trunnions or pivots "0. Thus movement ofthe piston from one end of the cylinder to the other will result in rotation of the segmental gear, the pinion and the drum I6I which through the chains will rotate the tubular supporting member I05. The cylinder is preferably operated by compressed air, the air being supplied through conduits (not shown) and controlled, for example, by conventional solenoid valves through push button controls positioned with the other controls at the operator's station adjacent the die stand. a In order to accurately locate the mandrel rods and mandrels in their two extreme positions of rotation. a stop member I1! is secured to the tube I05 as-shown in Figure 21. This stop is adapted to engage stop members I12 and H3 supported by the bed I0l; and which may be provided with pads H211 and II3a if desired. Thus in the posiestand is arran ed to takethe. thrust on thetiibe e25 flan shown. e nd o p. "I engages h pad I12a, whereas in the other extreme position with the positions of the mandrel rods reversed, the stop will engage the pad .I'Ila.

In this modification of the invention, the mechanism for loading tubes onto themandrels is also modified. It is to be understood, however, that the mandrel supporting mechanism of this modification may be used with the tube loading mechanism previously described, and the previously described mandrel loading apparatus embodying the elevating platform and pusher may be utilized if desired with the mandrel support of the present modification.

The tubes to be drawn are carried by a loadin rack indicated generally at I18 and positioned in conventional manner along the bed of the drawbench over which the carriage travels. In the present construction no elevating platform is provided, a supply of tubes merely being placed on a stationary platform made up of h rizontal members I18 carried by uprights I11. shown particularly in Figure 25, the horizontal portion of the rack is divided into two parts, a main storage portion I18 and a smaller trough portion I19 in which a few of the tubes to be drawn are placed by the operator as they are required.

In order to feed the tubes from the portion I18 over the mandrel rods I III or I I I, as the case may be, pinch rolls I88 and I 8| are provided. These are carried in a suitable framework I82, an air cylinder I83 being employed to urge the rolls to gether. The rolls are driven by a motor I84 through chain I85 and sprockets I88 and I81, the sprocket I81 being mounted on the shaft I88 which drives the upper pinch roll I80.

The lower pinch roll I 8I is supported by bearing, blocks I89 which are slidably mounted in frame members I 98, and thus-by means of the adjusting screws I9I, the pass level of the pinch rolls may be adjusted to accommodate tubes of different size. 'Preferably a guide member I82, having grooves in alignment with mandrel rods, is provided to assist the operator in guiding the tube onto the mandrel rods.

In order to load the mandrel rods with tubes, the operator merely feeds the tubes by hand into the bite of the pinch rolls and then manually guides the tubes onto the mandrel rods and within the mandrel rod supporting tubes. Thereupon the pinch rolls will feed the tubes over the mandrel rods, this operation being carried out while another set of tubes is being drawn through the dies by the carriage. Except for the difference-- in the operation of loading the tubes onto the mandrel rods, the apparatus of this modification is operated in substantially the manner previously described with reference to the first modification of the invention. In this last modification, however, additional fiexibility of operation is obtained by reason of the fact that the two sets of mandrel rods may be advanced and retracted independently of each other.

From the foregoing description of preferred forms of the invention it will be evident that the invention provides drawbenches which can be operated efiiciently and at high rates of production because of the fact that one set of mandrel rods can be loaded with tubes to be drawn during the operation of drawing tubes previously loaded onto the other set of mandrel rods. Drawbenches embodying the invention are of sturdy and rugged construction and may readily be adapted to drawing operations involving either the drawing of a single tube or to multiple drawing operations involving various numbers of tubes. Because of the 10 fact that the mandrels are loaded in horizontal position, the loadingracks may be horizontal, increasing the ease of handling the tubes on the racks and simplifying the design and construction 5 of the racks. The machines are such that all of the controls can be brought to a central point adjacent the die stand so that the benches can be operated by one man provided suitable mechanism is incorporated in the benches for dischargl0 ing the drawn tubes.

Various changes and modifications in my inventlon will be apparent to those skilled in the art. Therefore, it is to be understood that my patent is not limited to the preferred forms described herein or in any manner other than by the scope of the appended claims.

I claim:

'1. In a drawbench for tubes. said drawbenc having a die stand provided with a plurality of dies, a supporting frame extending in one direction from said die stand, a bed extending in the opposite direction from said die stand, and carriage means operating on said bed for pulling tubes through said dies; at least two groups of mandrel rods, tube supporting members associated with each mandrel rod and adapted to support the rod and a tube loaded thereon, all of the mandrel rods being substantially parallel with each other and with the center lines of said dies, so rotatable means supported by said frame for moving the mandrel rods of one group into drawing position in alignment with said dies while simultaneously moving the mandrel rods of the other group from drawing position into a loading position out of alignment .with said die, said rotatable means comprising a plurality of cage members carrying said tube supporting members, and a,

single anchor member to which the ends of the mandrel rods are secured, said cage members and *anchor member being supported bysaid frame for rotation about a common axis parallel to the axes of said mandrel rods, means for rotating said cage and anchor member simultaneously to interchange said groups of mandrel rods as aforesaid, 5 and means for shifting said anchor member simultaneously to advance and retract all of the mandrel rods toward and away from said die.

2. In a drawbench for tubes, said drawbench having a. die stand provided with a plurality of '50 dies, a supporting frame extending in one direction from said die stand, a. bed extending in the opposite direction from said die stand, and carriage means operating on said bed for pulling tubes through said dies; at least two groups of mandrel rods, all of the mandrel rods being substantially parallel with each other and with the center lines of said dies, and rotatable means supported by said frame for moving the mandrel rods of one group into drawing position in alignw ment with said dies while simultaneously moving the mandrel rods of the other group from drawing position into a loading position out of alignment with said die, said rotatable means com- 11 riage means operating on said bed for pulling tubes through said dies; at least two groups of mandrel rods, all of the mandrel rods being substantially parallel with each other and with the center lines of said dies, rotatable means supported by said frame for moving the mandrel rods of one group into drawing position in alignment with said dies while simultaneously moving the mandrel rods of the other group from drawing position into a loading position out of alignment with said die, said rotatable means comprising a cylindrcal member surrounding said mandrel rods and extending throughout the major portion of the length thereof, said cylindrical member being supported by said frame for rotation about an axis parallel to the axes of said rods and having means for supporting said rods within it, separate anchoring means for each group of mandrel rods, and means for individually shifting each anchoring means to movesaid mandrel rods toward and away from the die stand.

4. In a drawbench for tubes, said drawbench having a, die stand provided with a plurality of dies, a supporting frame extending in one direction from said die stand, a bed extending in the opposite direction from said die stand, and carriage means operating on said bed for pulling tubes through said dies; at least two groups of mandrel rods, tube supporting members associated with each mandrel rod and adapted to support the rod and a tube loaded thereon, all of the mandrel rods being substantially parallel with each other and with the center lines of said dies, rotatable means supported by said frame for moving the mandrel rods of one group into drawing position in alignment with said dies while simultaneously moving the mandrel rods of the other group from drawing position into a loading position out of alignment with said die, said rotatable means comprising a cylindrical member surrounding said mandrel rods and extending throughout the major portion of the length thereof, said cylindrical member being supported by said frame for rotation aboutan axis parallel to the axes of said rods and carrying said tube supporting members and mandrel rods within it, anchor means for said mandrel rods at the end of said cylindrical member remote from the die stand, means for rotating said cylindrical member, and means mounted within said cylindrical member for shifting said anchor means and said mandrel rods toward and away from said die stand. 1

5. In a drawbench for tubes, said drawbench having a die stand provided with a plurality of dies, a supporting frame extending in one direction from said die stand, a bed extending in the opposite direction from said die stand, and carriage means operating on said bed for pulling tubes through said dies; at least two groups of mandrel rods, tube supporting members associated with each mandrel rod and adapted to support the rod and a tube loaded thereon, all of the mandrel rods being substantially parallel with each other and with the center lines of said dies, rotatable means supported by said frame for moving the mandrel rods of one group into drawing position in alignment with said dies while simultaneously moving the mandrel rods of the other group from drawing position into a loading position out of alignment with said die, said rotatable means comprising a cylindrical member surrounding said mandrel rods and extending throughout the major portion of the length thereof, said cylindrical member being supported by said frame for rotation about an axis parallel to the axes of said rods and carrying said tube supporting members and mandrel rods within it, separate anchor means for each group of mandrel rods carried by said cylindrical member at the end thereof remote from the diestand, fluid pressure means for rotating said cylindrical member, and fluid pressure means mounted within said cylindrical member for shifting said anchor means and said mandrel rods toward and away from said die stand. a

6. In a drawbench for tubes, said drawbench having a die stand provided with a plurality of dies, a supporting frame extending in one direction from said die stand, a bed extending in the opposite direction from said die stand, and carriage means operating on said bed for pulling tubes through said dies, at least two groups of mandrel rods, tube supporting members associated with each mandrel rod and adapted to sup port the rod and a tube loaded thereon, all of the mandrel rods being substantially parallel with each other and with the center lines of said dies, rotatable means supported by said frame for moving the mandrel rods of one group into drawing position in alignment with said dies while simultaneously moving the mandrel rods of the other group from drawing position into a loading position out of alignment with said die, said rotatable means comprising a cylindrical member extending throughout the major portion of the length of said mandrel rods, said cylindrical member being supported by said frame for rotation about an axis parallel to the axes of said rods and carrying said tube supporting members and mandrel rods within it, anchor means for said mandrel rods at the end of said cylindrical member, means for rotating said cylindrical member, means mounted within said cylindrical member for shifting said anchor means and said mandrel rods toward and away from said die stand, said cylindrical member taking the thrust of said anchor means, and thrust bearing means at the end of said cylindrical member adjacent the die stand for transmitting the thrust to said frame member.

'7. In a drawbench for tubes, said drawbench having a die stand provided with a plurality of dies, supporting means extending in one direction from said die stand, a bed extending in the opposite direction from said die stand, and carriage means operating on said bed for pulling tubes through said dies, at least two mandrel rods, tube supporting members associated with each mandrel rod and adapted to support the rod and a tube loaded thereon, saidmandrel rods being substantially parallel with each other and with the center lines of said dies, rotatable means supported by said frame for moving one mandrel rod into drawing position in alignment with said dies while simultaneously moving another mandrel rod 7 from drawing position into a loading position out of alignment with said die, said rotatable means comprising a cylindrical member extending throughout the major portion of the length of said mandrel rods, said cylindrical member being supported by said supporting means for rotation about an axis parallel to the axes of said rods and carrying said tube supporting members and mandrel rods within it, and means for rotating said cylindrical member comprising a drum mounted for rotation about an axis parallel to and spaced from the axis of said cylindrical member, two flexible members having their ends secured respectively to said drum and to said cylin- 8. In a drawbench 'for tubes, said drawbench having a die stand provided with a plurality of dies, a bed extending from said die stand, and carriage means operating on said bed for pulling tubes through said dies, at least two groups of mandrel rods, tube supporting members associated with each mandrel rod and adapted to support the rod and a tube loaded thereon, all of the mandrel rods being substantially parallel with each other and with the center lines of said dies, rotatable means for moving the mandrel rods of one group into drawing position in alignment with said dies while simultaneously moving the mandrel rods of the other group from drawing position into a loading position out of alignment with said die, said rotatable means comprising a cylindrical member surrounding said mandrel rods and extending throughout the major portion of the, length thereof, said cylindrical member being supported for rotation about an axis parallel to the axes of said rods and carrying said tube supporting members and mandrel rods within it, anchoring means for said mandrel rods comprising anchor members abutting one end of said cylindrical member, the mandrel rods of one I Number group being secured to one of said anchor members and the mandrel rods of the other group being secured to the other of said anchor members, means carried within said cylindrical member for separately supporting said anchor members for movement parallel to the axis of the cylindrical member and toward and away from the end thereof, and fluid pressure means for each of said anchor members carried by said cylindrical member and adapted so to move said an- WILLIAM RODDER.

REFERENCES CITED The following references are'of record in the file of this patent:

UNITED STATES PATENTS Name Date 4 693,119 Diescher Feb. 11,- 1902v 1,963,047 Cowdery June 12, 1934 1,986,691 Uebelhart June 12, 1934 2,196,155 Smith Apr. 2, 1940 2,301,674 Andrews Nov. 10, 1942 2,320,235 Hjarpe Apr, 25, 1943 2,331,953 Andrews Oct. 19, 1943 FOREIGN PATENTS Number Country Date 441,822 Great Britain Jan. 2'7, 1936 

